GPG-Ezmlm is an encrypted mailing list. PGP or GPG encrypted mails sent to the list are re-encrypted with subscriber keys, allowing for encrypted mail communications without requiring that all users know all other users' keys. Key exchange during list subscription is supported. It requires an existing Ezmlm installation to function.

SmartPost is a complete email platform based on Davide Libenzi's xmail. It has Web interfaces for adding and managing email domains, for postmasters to manage their email users, and for users to send and receive email.

Enemies of Carlotta is a simple mailing list
manager. It tries to mimic the ezmlm software
somewhat, but is written completely from scratch
in Python. It has a less restrictive license than
ezmlm and qmail, and is smaller and simpler than
GNU Mailman.

eCRM is not an ordinary mailing list manager or an
ordinary mailto CGI; it is a small Web-based
customer relationship management system. It
contains many usefull functions for business
needs. With eCRM you can manage your customers
online and transfer them in to your normal
applications. Key features include address
management, ability to group customer records,
statistics about your customers, automatic form
creation that can be implemented on several Web
sites (mailto that stores the contact in the
database), and more.

Kerio MailServer is an email and collaboration suite that comes integrated with direct over-the-air (OTA) ActiveSync support, over 14 anti-spam layers (including SpamAssassin), dual anti-virus options (including a ClamAV plugin), collaboration features in Outlook, Entourage, Outlook Mobile, VersaMail, WebMail, and iCal, email archiving, and live automated backups. It supports a variety of SSL-encrypted communication protocols including POP3, IMAP, STMP, and HTTP for WebDAV, CalDAV, Web mail, and wireless ActiveSync. Wireless capabilities include direct email push, synchronization of calendar events, contacts, and tasks, and remote wipe for Windows Mobile devices to delete company data in the event the device is lost or stolen. Authentication options include Active Directory, Apple Open Directory, PAM, and an internal database. It can be administered remotely using an encrypted channel.

The Gordano Messaging Suite (GMS) is a highly
flexible and reliable suite of messaging products.
Customers can choose which components meet their
needs from email, Webmail, collaboration, instant
messaging, calendaring, SMS, and list server
software all of which can be complimented by high
level anti-spam, anti-virus, and archiving
options.